Map of Petit lac Brompton with depth contours

Petit lac Brompton

45.4499° N, 72.1011° W

Depth contours from the 2012 government survey. Not for navigation.

Download the depth map (SVG)

Petit lac Brompton is 19.4 m deep at its deepest point, deeper than 61% of the 1,506 surveyed lakes in Quebec. It covers 0.72 km² and lies beside Lac-Desmarais.

Maximum depth
19.4 msurveyed 2012
deeper than 61% of the 1,506 surveyed lakes in Quebec
Area
0.72 km²
larger than 69% of the 29,407 lakes in Quebec
Shoreline
4.2 km
longer than 55% of the 29,407 lakes in Quebec
Water clarity
4.8 mSecchi depth, 2025
clearer than 68% of the 805 monitored lakes in Quebec
Elevation
262 m

Today on the water

YELLOW ADVISORY - FROST · issued 8:47 a.m. EDT
Temperatures will drop to near freezing overnight tonoght as well as overnight Saturday to Sunday.

Take preventative measures to protect cold-sensitive plants, trees, and crops.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to QCstorm@ec.gc.ca or post reports on social media using #QCStorm.

Official alert on weather.gc.ca · expires 12:47 a.m. EDT Saturday

7.9 °C

CloudyWind W 15 km/h

Observed at Sherbrooke, as of 9:06 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 10 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Hourly forecast, next 24 hours
Time10 a.m.1 p.m.4 p.m.7 p.m.10 p.m.1 a.m.4 a.m.7 a.m.
Wind km/hW 20W 20W 20W 20W 15W 10W 10W 15
Gusts km/h404040
Waves (est.) m0.20.20.20.2
Temp. °C9111186420
Precip. %404040400000

Today: Mainly cloudy with 40 percent chance of showers. Risk of a thunderstorm late this afternoon. Wind becoming west 20 km/h gusting to 40 this morning. High 12. UV index 3 or moderate.

Weather: Sherbrooke (local forecast), as of 9:07 a.m. EDT

Sun and moon

Civil dawn
6:27 a.m.
Sunrise
6:56 a.m.
Sunset
6:13 p.m.
Civil dusk
6:43 p.m.
Moonrise
5:47 a.m.
Moonset
5:31 p.m.
Moon
Waning crescent, 1% lit

Data Source: Environment and Climate Change Canada. Local times.

How waves are estimated

Significant wave height from the forecast hourly wind and the open-water distance (fetch) upwind, using the SMB method (US Army Corps of Engineers Shore Protection Manual, 1984), rounded up to the next 0.1 m. It is not a measurement: gusts, leftover swell and shoals can make water rougher. Under 0.2 m: calm; 0.2–0.5 m: choppy; over 0.5 m: rough.

Depth

29% of Petit lac Brompton is deeper than 10 m.

How to read it: the lake’s area is sorted from the shore to the deepest point. Where the curve is flat, large areas share one depth (flats and weed beds); where it drops, depth changes quickly (drop-offs).

The government depth survey from 2012 records a maximum depth of 19.4 m, drawn from 28 depth contours.

Not for navigation. Depths are from government surveys and may be outdated.

Water

Trophic status from the latest monitoring: oligo-mesotrophic (transition).

Clarity was measured with a Secchi disk in 3 years between 2023 and 2025; the latest annual mean is 4.8 m.

Water clarity (Secchi depth, m)
Total phosphorus (µg/L)